The majority of personal care products in the market today are sold as liquid products. While widely used, liquid products have disadvantages in terms of packaging, storage, transportation, and convenience of use. Liquid personal care products typically are sold in bottles which add significant cost as well as packaging waste, much of which ends up in land-fills.
Solid hair dyes are known, but generally discussed in terms of powdered oxidative dyes that are mixed with a developer solution before application onto the hair. Such products still require a traditional kit of dye and developer compositions.
Solid personal care products in the form of dissolvable foams are also known. See WO 2010/077650. U.S. Pat. No. 7,225,920 B2 discusses a bleaching composition sealed into a water soluble pouch that is then dissolved in water. EP 1745769 B1 discusses a liquid that is foamed and then dries to form a hair coloring product. U.S. Pat. No. 5,879,414 A discusses a hydrous solid wash resistant hair colorant stick composition. US 2003/0033678 discusses a shaped body useful for forming cosmetic preparation such as hair coloring preparations. U.S. Pat. No. 5,769,901 discusses a powdered hair dye including an oxidative dye component, an oxidizing component and a thickening component.
There still exists a need to provide a soluble solid hair coloring product that is stable and delivers desired hair color results. It has surprisingly been found that the selection of anionic surfactant in the porous solid must be compatible with the desired direct dyes in order to provide a hair colorant. As direct dyes are essentially salts, it is not obvious as to how such direct dyes will affect formulated product and stability of the formulated product. A balance must be found between delivering the desired color results and producing a stable product that is robust in view of the salt levels present.
It is an object of the present invention to provide a soluble hair coloring product from an open-celled porous solid that can be conveniently and quickly dissolved in the palm of the consumer to reconstitute a liquid product for ease of application to hair while providing sufficient topical delivery of active agents for partial or whole head hair applications with similar performance as today's liquid products. It is a further object of the present invention to provide such a product that can be produced by physical aeration followed by subsequent drying. It is an even further object of the present invention to provide such a product with desirable softness and flexibility.